Radical Chemistry of Flavonoid Antioxidants

Bors, Wolf; Heller, Werner; Michel, Christa; Sarán, Manfred

doi:10.1007/978-1-4684-5730-8_25

Cited by 134 publications

(117 citation statements)

References 14 publications

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“…The structural diŠerences among Pel, Cy, and Del lies only in the number of hydroxyl groups on the ring B. A catechol moiety in the B ring of ‰avonoids lends high stability to the aroxyl radical via hydrogen bonding 11) or by expanded electron delocalization.…”

Section: Inhibition Of Linoleic Acid Hydroperoxide-induced Toxicity Imentioning

confidence: 99%

Inhibition of Linoleic Acid Hydroperoxide-induced Toxicity in Cultured Human Fibroblasts by Anthocyanidins

Kaneko

Tahara

Baba

2003

Bioscience, Biotechnology, and Biochemistry

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Section: Inhibition Of Linoleic Acid Hydroperoxide-induced Toxicity Imentioning

confidence: 99%

Inhibition of Linoleic Acid Hydroperoxide-induced Toxicity in Cultured Human Fibroblasts by Anthocyanidins

Kaneko

Tahara

Baba

2003

Bioscience, Biotechnology, and Biochemistry

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“…decrease in seed weight, increase in pyrimidine glucosides), consequent to tannins removal, should be carefully evaluated (8,9). Tannins are considered to be involved in the plant defence mechanism to environmental attack, likely because of the recently reported antioxidant properties (10)(11)(12). Indeed, tannins and other plant polyphenols (anthocyanins, flavonoids) are receiving growing interest as possible protective factors against free radicalmediated pathologies in men, such as cancer and atherosclerosis (13).…”

Section: Introductionmentioning

confidence: 98%

Evidence for Protein–Tannin Interaction in Legumes: Implications in the Antioxidant Properties of Faba Bean Tannins

Carbonaro

Virgili

Carnovale

1996

LWT - Food Science and Technology

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Section: Document Version Publisher's Pdf Also Known As Version Of Rmentioning

confidence: 99%

“…It cleaves the O-heterocycle of polyphenolic flavonols ( Figure 1a) which represent a major class of flavonoids (12). These compounds are important dietary components and have attracted considerable attention in the past decade owing to their antioxidizing properties (13)(14)(15).Recently, our group has elucidated the X-ray structure of 2,3QD from Aspergillus japonicus at 1.6 Å resolution (PDB code 1JUH (16)) providing the first structural view of a noniron dioxygenase. The enzyme is a homodimer of ∼100 kDa.…”

mentioning

confidence: 99%

Functional Analysis of the Copper-Dependent Quercetin 2,3-Dioxygenase. 1. Ligand-Induced Coordination Changes Probed by X-ray Crystallography: Inhibition, Ordering Effect, and Mechanistic Insights

2002

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Functional analysis of the copper-dependent quercetin 2,3-dioxygenase. 1. Ligand-induced coordination changes probed by X-ray crystallography Steiner, Roberto A.; Kooter, Ingeborg M.; Dijkstra, Bauke W. IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document Version Publisher's PDF, also known as Version of record Publication date: 2002Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Steiner, R. A., Kooter, I. M., & Dijkstra, B. W. (2002). Functional analysis of the copper-dependent quercetin 2,3-dioxygenase. 1. Ligand-induced coordination changes probed by X-ray crystallography: Inhibition, ordering effect, and mechanistic insights. Biochemistry, 41(25), 7955-7962. DOI: 10.1021/bi0159736 Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. ReceiVed NoVember 26, 2001; ReVised Manuscript ReceiVed May 7, 2002 ABSTRACT: The crystal structures of the copper-dependent Aspergillus japonicus quercetin 2,3-dioxygenase (2,3QD) complexed with the inhibitors diethyldithiocarbamate (DDC) and kojic acid (KOJ) are reported at 1.70 and 2.15 Å resolution, respectively. Both inhibitors asymmetrically chelate the metal center and assume a common orientation in the active site cleft. Their molecular plane blocks access to the inner portion of the cavity which is lined by the side chains of residues Met51, Thr53, Phe75, Phe114, and Met123 and which is believed to bind the flavonol B-ring of the natural substrate. The binding of the inhibitors brings order into the mixed coordination observed in the native enzyme. DDC and KOJ induce a single conformation of the Glu73 side chain, although in different ways. In the presence of DDC, Glu73 is detached from the copper ion with its carboxylate moiety pointing away from the active site cavity. In contrast, when KOJ is bound, Glu73 ligates the Cu ion through its O 1 atom with a monodentate geometry. Compared to the native coordinating conformation, this conformation is approximately 90°rotated about the 3 angle. This latter Glu73 conformation is compatible with the presence of a bound substrate.Dioxygenases are enzymes that catalyze the incorporation of both atoms of molecular oxygen into organic substrates. They take part in the metabolism of biomolecules as different as amino acids, lipids, nucleic acids, and even carbohydrates (1...

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Radical Chemistry of Flavonoid Antioxidants

Cited by 134 publications

References 14 publications

Inhibition of Linoleic Acid Hydroperoxide-induced Toxicity in Cultured Human Fibroblasts by Anthocyanidins

Inhibition of Linoleic Acid Hydroperoxide-induced Toxicity in Cultured Human Fibroblasts by Anthocyanidins

Evidence for Protein–Tannin Interaction in Legumes: Implications in the Antioxidant Properties of Faba Bean Tannins

Functional Analysis of the Copper-Dependent Quercetin 2,3-Dioxygenase. 1. Ligand-Induced Coordination Changes Probed by X-ray Crystallography: Inhibition, Ordering Effect, and Mechanistic Insights

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